Connector devices for securing a tubular member to another tubular member or for example to support structure are used commonly in the construction of handrails and balustrades. The connector devices usually are required to provide a smooth surface in combination with the end of a tube to which they are connected and to interconnect with that tube in a tamper resistant manner. A difficulty arises in that a considerable number of such connectors are needed, and are required to be held in stock, in order to interconnect different size tubes and allow interconnection of the tubes at any of a range of relative positions. Articulated type connection devices have been proposed but these generally suffer the disadvantage of being incompatible with providing a smooth and tamper resistant interconnection.